Hinchey Classification for Diverticulitis
The Hinchey classification is a four-stage system that categorizes acute colonic diverticulitis based on the extent of infection and inflammation beyond the colon, guiding treatment decisions from conservative management to emergency surgery. 1, 2
Original Hinchey Classification Stages
The original Hinchey classification consists of four progressive stages 1, 2:
Stage 1 (Hinchey I): Pericolic abscess or phlegmon - localized infection confined to the area immediately surrounding the colon 2
Stage 2 (Hinchey II): Pelvic, intra-abdominal, or retroperitoneal abscess - infection has spread beyond the pericolic area but remains contained 2
Stage 3 (Hinchey III): Generalized purulent peritonitis - rupture with pus throughout the abdominal cavity 1, 2
Stage 4 (Hinchey IV): Fecal peritonitis - rupture with fecal contamination throughout the abdominal cavity, representing the most severe form 1, 2
Modified Hinchey Classification
The Modified Hinchey Classification incorporates CT imaging findings for more precise diagnosis and includes additional substages 1, 2:
Stage 0: Mild clinical diverticulitis without CT evidence of complications 2
Stage 1a: Confined pericolic inflammation or phlegmon 1
Stage 3: Generalized purulent peritonitis 1
Stage 4: Fecal peritonitis 2
Clinical Management Based on Hinchey Stage
CT imaging is essential for accurate classification and management planning - relying solely on clinical examination is not recommended due to poor accuracy 2.
Treatment Algorithm by Stage:
Hinchey 1a (phlegmon): Conservative management with bowel rest and antibiotics 1
Hinchey 1b (small abscess <4 cm): Non-operative management with bowel rest and antibiotics 1, 2
Hinchey 2 (larger abscess >4 cm): Percutaneous CT-guided drainage is recommended 1, 2
Hinchey 3 (purulent peritonitis): Surgical intervention required, though laparoscopic lavage may be considered in highly selected patients 3
Hinchey 4 (fecal peritonitis): Emergency surgical resection required 3
Important Clinical Considerations
Abscess size matters significantly for outcomes: Patients with CT evidence of an abscess have a 22.2% failure rate with conservative treatment compared to only 6.8% in those without abscess, and recurrence rates reach 41.2% for pelvic abscesses (Stage II) treated conservatively 4.
The Hinchey classification predicts surgical need with high accuracy: Both the original and modified systems demonstrate area under the curve values of 0.80-0.83 for predicting need for operative intervention and complications 5.
Common pitfall: Failure to obtain CT imaging may lead to misclassification and inappropriate management, as clinical examination alone is inadequate for accurate staging 2.